Questions tagged [experiment-design]

The study of how to structure an information-gathering exercise where variation is present.

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47 views

Treatment combinations in different blocks for a $2^6$ design with partial confounding

Let us consider a $2^6$ design in 8 blocks with ABCD, BCE and ADEF as independent effects are chosen to be confounded with blocks. Q.1 $\:$ Write down the treatment combinations in the principal ...
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Seeking clarification for research questions in a quasi-experimental study? [closed]

For not addressing the question posted as I am a novice researcher. But interested to share questions of mine. I conducted a quasi-experimental study to evaluate effectiveness of a method of teaching, ...
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Should I apply my treatment as a continuous gradient, or in blocks?

I am designing an experiment, and am looking for advice on how to apply my treatment most efficiently. I'll give an example to explain. My response is car efficiency - how many miles per gallon of ...
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Design of experiments and building a logistic-regression-like model

Consider a population characterized in terms of a small number of categorical features (age category, income bracket, gender, level of education, etc.). I am interested in how these features affect ...
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Adequate statistical method to compare objective measure vs estimations

I am using a software for image recognition to do the following: calculate the percentage of a surface that is painted black. On the other hand, there are several observers that estimate the ...
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Two-way ANOVA/GLM for 2x3 incomplete factorial design

I am designing a within-group study with two factors (fixed novelty, levels: old, new; and indexical novelty, levels: veridical, statistical, new; so a 2x3). Now, ideally, I would just cross these ...
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Pick a subset with best (propensity score) matched samples

I am running a matching algorithm to matching patients in a treatment group to patients in a control group without replacement. Say there are $n_T$ treatment group patients and $n_C$ control group ...
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What's the right way to do Bootstrapping Analysis on UserId Randomized A/A?

My motivation is to do A/A analysis using the "Bootstrap" method to calculate the confidence interval of the "sample mean" (of treatment and control) of all metrics. In my A/B ...
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Can I add a random effect in a mixed effect model accounting for huge differences within factors?

Update 1 Progress I tried some modifications to my models an got lost of the interaction (1|year:row) since the random intercept of row shouldn’t differ between the ...
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what is trial in my experiment?

I have a basic question about the exact meaning of trial in experimental designs. My experiment includes presenting three rhythmic patterns (each consisting of 5 sounds) to participants and they're ...
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How can I compare whether different levels of factor causes the measurement to vary more than the other?

Suppose that I have a set of certain measurement. There are two factors that can affect the value of the measurement, let's call them the factors $A$ and $B$. The factor $A$ has 2 levels (levels 1 and ...
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How to calculate sample size for blocked-design two-way ANOVA?

Does anyone know of a good online calculator or at least a good paper that details how to calculate the needed sample size for a blocked-design two-way ANOVA experiment? I've seen a ton of references ...
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Calculating required sample size using the effect size obtained from a (slightly) different population and exprimental intervention?

I am trying to work out an appropriate sample size for a study looking to improve the consciousness of vegetative state patients using low-intensity focused ultrasound stimulation as evaluated with ...
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Crop growth simulation model with differential equations? Advice to design experiment

I'm interested in designing an experiment to simulate the plant domestication process over a few thousand years. I have a few hypotheses about specific plant traits I want to test by creating a ...
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How do I analyze bimodal distibuted data with a linear mixed model

The experiment I am working on has the following design: A B C D E F B A D E F C A B E F C D B A F C D E Each Letter represents a different level of the single factor called “...
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which package for full factorial experiment (5 parameters, 3 levels)?

I'm looking for a (convienent) package for r to construct an experiment design for five parameters and three levels (full factorial). I'm only used to ...
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How to Optimize Using RSM and Central Composite Design

I am learning about Central Composite Designs (CCD) and I am wondering how one chooses the center and the range that the factorial corners span. For example, if I am optimizing the yield of a chemical ...
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What statistical test is needed for this experiment? Is it a simple t-test?

Suppose I have data which is something like the table below, where I measure how an individual does on a task under 4 conditions. So we observe A, B, C, D for a given individual. There are $N$ ...
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22 views

Change parameters block-wise in experiment design?

Is it possible to generate an experiment design which changes a parameter block-wise? To be more precise what I would like to do: Run an experiment with a certain parameter (humidity) fixed which is ...
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Is adding conceptual sub-units to a model to deal with repeated measurements appropriate?

I've been contemplating this question by @user7937045 (Permutation test - can I apply it here?). The linked question is regarding whether or not it's ok, or even preferred, to use a permutation-...
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Help Identifying Experiment Design

I'm hoping for some help identifying the experiment design in this question: A large bakery would like to run an experiment that consists of evaluating the volume of their cupcakes after baking. Four ...
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Can we say delta% is significant if delta is significant?

The question is simple. As for most of the online A/B test, we are more interested in the delta% than delta, for example: ...
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1answer
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Determining if linear regression is appropriate

I am designing an experiment, and I want to know if using a hypothesis test on the linear regression model to analyze my data is appropriate. The experiment will have five independent variable values ...
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Regression after matching

I performed 1:1 nearest neighbor matching on 16 covariates using matchit package on R. Covariate balance looks good for most covariates, but there are some that looks less than ideal. I then ran ...
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Selection of stats test for non-normal data

in the early days of PhD and still a bit useless with stats. Here's my question. So for context, say for example I have an experiment where I take cells from 10 humans in total (e.g. Monocytes) and I ...
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Do I have to use one model, or can I use multiple tests? (which statistical test to use for a survey with both within and between subjects questions)

I am conducting a survey and am wondering what analysis to use, and if I need to use a model which analyses everything at once or if two separate tests can be used. The experiment is based on a 3 by 2 ...
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How to perform power analysis for sample size decision in bootstrapping

I want to test my null hypothesis that there is no difference between the 80th percentile of the two groups with AB testing. First, I'd like to decide sample size. If it were mean comparison, I can ...
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Coding systematic designs with multiple random starts

I am trying to set up a survey design using the survey package. We sampled 0.5m transects systematically from a 100m reach and used 3 random start locations thinking it would provide a better ...
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Calculating the variance in throws made by a juggling machine

I have built a juggling machine. It has no sensors and moves in a consistent programed motion. In my attempts to make the machine juggle for as long as possible, I have been studying the accuracy of ...
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Block design or completely randomized?

I have 5 conditions in my experiment: A,B,C,D,E and my sample size is 200 subjects. I want to have 40 subjects per condition, so I assign a condition to a person randomly without replacement. E.g. ...
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Evaluate change in participant population characteristics

The Project I'm doing an analysis concerning a major drop in service uptake since the beginning of COVID. I have access to administrative data for those using services, including relevant demographic ...
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Identify two points from a set as similar

I'm trying to build a model to asses different physiological parameters (Dry weight, yield, Nitrogen concentration, one model for each) from a field based on reflectance from different wavelengths i.e....
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Random sampling error vs. test statistics

I've been told many times in my school, that after you analyze your data and get statistically significant results, you can say that the result is not due to chance and therefore you can conclude that ...
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How to estimate population statistics for each category?

I have data from a simple random sample having n elements which I’m using as an unbiased estimate for my population statistics (mean). My population can be divided into k categories, and I know the ...
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Hierarchical linear model in the context of an experiment

In an experimental study, I randomly assign participants to one of two conditions: Condition A (which they read Text A), and Condition B (in which they read Text B). After reading their assigned text, ...
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How to model partially crossed fixed effect?

in an experiment I manipulated two treatments A and B. A has three levels (A1, A2, A3) and B has three levels (B1, B2, B3). A and B are partially crossed so that there are 5 treatment combination: ...
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Why do interaction terms work?

I am currently trying to develop a better intuition for interaction terms in linear models. And, conveniently, it turns out, if I concentrate on $\hat{y}$, it doesn't matter what kind of contrasts are ...
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Nonparametric assessment of multiple predictors

What statistical analysis should I use when I have two or more continuous independent predictor variables and two or more dependent variables to be predicted? I cannot assume normal distribution. I ...
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Re-randomization in Experimental Design

I am struggling to synthesize the objections to re-randomization in experiments when it is costless and the criteria are pre-specified and regression is not an option. This came up in a related ...
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Translation of between-subject sample sizes to within-subject sample sizes

The following formula can be used to translate the sample size needed from one way between-designs (NB) to sample sizes needed in one way within-designs (NW): NW = NB(1 − ρ)/number of data points per ...
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bootstrap rows of a regression data frame even though the predictors are not random variables?

I got some inspiration from a question that was posted this morning. Let's design an experiment where we have three factors, each with two levels (e.g. male/female). This gives a total of eight groups,...
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what type of analyses to use if one of the dependent variables is omitted when another dependent variable takes a certain value?

I have one independent variable (IV) and two dependent variables (DV1 and DV2). DV1 can take value 0 or 1. DV2 can take a value between 1 and 7 only if DV1 is 1. If DV1 is 0, then DV2 is omitted. As ...
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How much time between testing for comparison of survey-methods

Consider one came up with a new surveying method, for example an application that relies on some form of gamification of question-answering and wanted to compare how participants would use it to ...
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Does 'As Good As Random' Have a rigorous definition in identification strategies?

If using an identificaton strategy such as differences in differences, Regression Discontinuities, or IV's, I see the phrase 'as good as random' used alot. Does this have a rigorous definition, or is ...
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Experimental Design Problem with Goofy Constraints

I am having trouble designing an experiment. I will give a hypothetical example that shares the main features of my actual problem. Suppose there are: $M$ meadows, indexed by $m={1,...,M}$, where $M \...
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Is it statistically valid to use K Means to cluster fitted respondent part worth utilities from Conjoint Analysis(Hierarchial Bayes Multinomial Logit)

Introduction: My team used Conjoint.ly to run a conjoint analysis survey to do market research. From https://conjointly.com/guides/conjoint-technical-notes/: Conjoint.ly estimates a hierarchical ...
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27 views

How to select a Multiple Comparisons Test based on power?

As background, multiple comparison tests (MCT) are a new topic for me. I am currently planning the data analysis for an experiment and see that an MCT is needed. It seems that a key differentiating ...
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Comparing intervention group vs whole (mixed) population

For practical reasons I can not apply classic study design, that is to compare intervention group vs control group. I only have data for a sample of an intervention group and the whole population ...
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What statistical test is appropriate for the following experimental design, apart from mixed two-way ANOVA?

We are planning a study of the effectiveness of two therapies for treating depression. Group A will receive the current therapy and group B will receive a new and improved therapy. Participants are ...
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Why “sorting” is needed for simple random sampling [closed]

Tutorials demonstrating simple random sampling, first list the full number of population members (i.e., sampling frame) in a column and then assign a random number from $0$ to $1$ from a uniform ...

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